A method for the preparation of a high-bonding geopolymer coating for cement-based surfaces

Abstract

The application discloses a preparation method of a high-adhesion geopolymer coating for a cement-based surface, and comprises the following steps: mixing sodium silicate and H2O to obtain a transparent alkali activator; weighing slag and the alkali activator, and then mixing and stirring to obtain a geopolymer precursor in a flow state; mixing organic material and nano-TiO2 in water to obtain a modified liquid; adding the modified liquid into the geopolymer precursor to obtain a super-hydrophobic coating; and brushing or spraying the prepared super-hydrophobic coating on the surface of a cement-based material after curing for 28 days to prepare a super-hydrophobic surface coating of the cement-based material. The geopolymer super-hydrophobic cement-based coating prepared by the preparation method of the super-hydrophobic coating for the cement-based surface meets the requirements of super-hydrophobic materials, a new type of inorganic coating, i.e., geopolymer, is used, the bonding strength of the coating and the base is improved, the coating has excellent adhesion, and the method has the advantages of simple process, high efficiency, non-toxicity, environmental protection, low carbon and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coatings and painting technology, in particular to a preparation method of a high-adhesion geopolymer coating for cement-based surfaces. BACKGROUND

[0002] Cement-based materials refer to engineering materials that use cement as a cementing material. They have been widely used in infrastructure construction due to their advantages such as abundant raw materials, low price, and good performance. However, the hydrophilicity and porosity of traditional cement-based materials allow water to easily penetrate into their interior, causing deterioration of their physical and mechanical properties. In particular, in humid coastal areas, the entry of external water severely affects the service life of cement-based materials. To improve the impermeability of cement-based materials and enhance their durability, superhydrophobic surfaces with micro-nano structures can be constructed based on the lotus effect.

[0003] There have been related studies on the preparation of superhydrophobic cement-based coatings at home and abroad. A paper (Construction and Building Materials, 2020, 247: 118-563) proposed a nano-mixing method to create a superhydrophobic concrete surface. This method combines the densification and reinforcement of nano-SiO2 and the use of n-propyl triethoxysilane to obtain superhydrophobic properties of the substrate. Patent CN108002860B discloses a method for superhydrophobic treatment of a concrete surface. Silane resin modified by kowyl trihexyloxy silane or heptadecafluorokowyl trimethoxysilane is sprayed on the roughened concrete surface, and nano-SiO2 and nano-CaCO3 are added to the coating to obtain superhydrophobicity. Although the above methods can significantly reduce water absorption and improve hydrophobicity, they have poor adhesion to the substrate.

[0004] Researchers have proposed various methods to solve the above problems. A paper (Cement & Concrete Composites, 2014, 52: 81-90) used a template method to cast concrete in a rough PDMS mold to create a rough structure, and then sprayed a hydrophobic coating on the surface to obtain superhydrophobicity. Patent CN105032731A discloses a preparation method for a superhydrophobic coating. This method uses commercial fumed SiO2 modified with fluorosilane, and then mixes it with resin in a certain proportion to obtain a superhydrophobic coating. A paper (Journal of Materials Research and Technology, 2022, 21: 4281-4298) introduced epoxy resin as a "binder" to achieve super-stable "welding" using three-dimensional cross-linking properties, and obtained a layered superhydrophobic coating with excellent mechanical stability. The above superhydrophobic surfaces have good adhesion, but still have problems such as complex process, high price, and environmental pollution.

[0005] Geopolymer is a kind of alkali metal aluminosilicate, which is made of solid waste materials such as slag as basic elements, under the action of alkaline activator, through dissolution, monomer reconstruction, low temperature polycondensation. Geopolymer-based protective coating is a new type of inorganic coating with superior performance, which has the advantages of high durability, good air permeability, not easy to age, high bonding strength and good compatibility with base layer. Therefore, it is of great significance to combine the excellent performance of geopolymer coating with waterproofness and develop geopolymer coating with super-hydrophobic property. It has practical significance to modify the geopolymer coating to super-hydrophobic at low cost and simply, so that it has excellent super-hydrophobicity and high adhesion. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of high adhesion geopolymer coating for cement-based surface, to solve the problems of poor adhesion between super-hydrophobic cement-based coating and substrate, complex process, high price and environmental pollution.

[0007] To achieve the above purpose, the present application provides a preparation method of high adhesion geopolymer coating for cement-based surface, comprising the following steps:

[0008] (1) mixing sodium silicate and H2O to obtain transparent alkali activator;

[0009] (2) weighing slag and alkali activator, then mixing and stirring to obtain geopolymer precursor in a flow state;

[0010] (3) mixing organic material and nano-TiO2 in water to obtain modification liquid;

[0011] (4) adding the modification liquid to the geopolymer precursor to obtain super-hydrophobic coating;

[0012] (5) brushing or spraying the prepared super-hydrophobic coating on the surface of cement-based material after curing for 28 days to obtain cement-based super-hydrophobic surface coating.

[0013] Preferably, in step (1), sodium silicate and H2O are mixed for 15 minutes, and sealed and stored for 24 hours before use, to obtain alkali activator with modulus of 1.6-2.0.

[0014] Preferably, in step (2), the molar ratio of Si / Al is 2.8-3.6, and the water-solid ratio is 0.9-1.1, and the geopolymer precursor is obtained by stirring for 20 minutes.

[0015] Preferably, the mass ratio of sodium silicate, water and slag is 14-15:50:50.

[0016] Preferably, the mass ratio of the organic material to water in the modifying liquid in step (3) is 10:50, and the added amount of nano-TiO2 is 1-3% of the total mass of the modifying liquid.

[0017] Preferably, the organic material in step (3) is one or a mixture of n-octyl triethoxysilane or propyl trimethoxysilane, and is mixed with nano-TiO2 and stirred for 3-4 hours to obtain the modifying liquid.

[0018] On the basis of the relatively dense geopolymer material, the addition of the organic material (silane) can form Si-O-Si bonds with the geopolymer gel to make the gel relatively loose, and the cured silane and the Si-O-Si gel phase and the loose gel phase increase the nanometer roughness of the sample. At the same time, the reaction of silane and Si-O-Si bond makes the gel phase connect with the functional group -CH3 with low surface energy, thereby making the geopolymer hydrophobic, and the silane prevents the polymerization process of the geopolymer to some extent, resulting in some unreacted slag particles remaining, which increases the surface micrometer roughness. The nanometer material titanium dioxide participates in the formation of hydrated silicic acid (C-S-H) through reaction, enhances the roughness of the surface and the interior of the material, and cooperates with low surface energy substances to make the coating meet the requirements of super-hydrophobic materials.

[0019] Preferably, in step (5), the mass ratio of Portland cement, fine sand and water in the cement-based material is 1:2.4-3:0.4-0.6.

[0020] Preferably, the total thickness of the coating formed in step (5) is between 0.5 and 4 mm.

[0021] Preferably, the total thickness of the coating formed in step (5) is between 2.5 and 3 mm.

[0022] Preferably, the particle size of the nano-TiO2 in step (1) is 30 nm.

[0023] Therefore, the preparation method of the high-adhesion geopolymer coating for the surface of a cement-based material has the following beneficial effects:

[0024] (1) The new geopolymer inorganic coating in the present application belongs to the field of new green building materials, and is suitable for the fields of civil engineering and civil building engineering, can prevent material corrosion and prolong the service life, and is composed of solid and liquid components, and after mixing and blending, is applied by brushing or spraying, and after hardening, is tightly combined with the base body and forms a "defense line" against external effects.

[0025] (2) The geopolymer coating of the present application is mainly prepared from inorganic industrial by-products or solid wastes as raw materials, the main raw material is abundant in source, low in cost, and the pollution of fluorine-containing organic matter to the environment is avoided, and the geopolymer coating is non-toxic, environment-friendly, and convenient for large-area use, and is suitable for surface protection of civil engineering or building structure.

[0026] (3) The geopolymer-based protective coating of the present application is a new type of inorganic cementitious coating, the coating has good bonding effect with the cement matrix, the tensile stress can reach 0.8 MPa, and Ca(OH)2 in the cement matrix reacts with Si and Al active components contained in the geopolymer coating to transfer from the cement matrix to the geopolymer coating, thereby promoting the formation of C-A-S-H type gel in the interface transition zone and improving the bonding strength.

[0027] (4) The new geopolymer inorganic material of the present application forms a composite material with common organic materials (silane), and the advantages of organic coatings and inorganic coatings are complementary, so that the surface protection effect is maximized.

[0028] (5) The geopolymer coating of the present application has the advantages of simple preparation process, high adhesion, excellent water repellency, corrosion resistance and the like.

[0029] The technical solutions of the present application will be further described below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a contact angle diagram of embodiment 4 of the present application;

[0031] Figure 2 is a macroscopic static phenomenon of embodiment 4 of the present application;

[0032] Figure 3 is a sandpaper abrasion performance curve diagram of embodiment 4 of the present application;

[0033] Figure 4 is a bonding stress curve diagram of embodiment 4 of the present application;

[0034] Figure 5 is a surface microstructure of embodiment 4 of the present application. DETAILED DESCRIPTION

[0035] The present application will be further described below, and it should be noted that the present embodiment is based on the technical solutions, and detailed implementation modes and specific operation processes are given, but the present application is not limited to the present embodiment. Example 1

[0036] A preparation method of a high-adhesion geopolymer super-hydrophobic coating, the specific steps are as follows:

[0037] Step 1, cement-based material preparation:

[0038] Put Portland cement, fine sand and water into the grinding tool in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0039] Step 2, alkali activator preparation:

[0040] Mix and stir 14.7g sodium silicate and 50g H2O in a magnetic stirrer at 800rmp / min for 15 minutes, seal and store for 24 hours before use, to obtain an alkali activator with a modulus of 2.0.

[0041] Step 3, geopolymer precursor preparation:

[0042] Weigh 50g of slag and the alkali activator prepared in step 2, mix and stir for 10 minutes to obtain a geopolymer precursor in a flowing state.

[0043] Step 4, preparation of modified liquid:

[0044] Dissolve 2% of nano-TiO2 (30nm) by mass of the total mass of the modified liquid in 50g of deionized water, and magnetically stir at room temperature for 3.5h at a speed of 1000rmp / min.

[0045] Step 5, modification of geopolymer coating:

[0046] Add the modified liquid to the geopolymer precursor, and stir at 30°C using a magnetic stirrer at a speed of 850rmp / min for 45 minutes to obtain a geopolymer-based super-hydrophobic coating.

[0047] Step 6, spraying or brushing on the cement-based surface cured for 28d:

[0048] Using brushing or spraying, apply the prepared geopolymer-based super-hydrophobic coating to the cement-based surface cured for 28d, and perform normal temperature curing, to obtain a geopolymer-based super-hydrophobic coating for the cement-based surface. The total thickness of the coating is 0.7mm. Example 2

[0049] A method for preparing a geopolymer super-hydrophobic coating with high adhesion, the specific steps are:

[0050] Step 1, cement-based material preparation:

[0051] Put Portland cement, fine sand and water into the grinding tool in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0052] Step 2, alkali activator preparation:

[0053] Mix 14.7 g sodium silicate and 50 g H2O in a magnetic stirrer at 800 rmp / min for 15 minutes, seal and store for 24 hours before use, to obtain an alkali activator with modulus of 2.0.

[0054] Step 3, preparation of geopolymer precursor:

[0055] Weigh 50 g of slag and the alkali activator prepared in step 2, mix and stir for 10 min to obtain a geopolymer precursor in a flowable state.

[0056] Step 4, preparation of modification liquid:

[0057] Dissolve 10 g of n-octyl triethoxysilane in 50 g of deionized water, and stir at room temperature for 3.5 h at a speed of 1000 rmp / min.

[0058] Step 5, modification of geopolymer coating:

[0059] Add the modification liquid to the geopolymer precursor, and stir at 30°C for 45 min at a speed of 850 rmp / min using a magnetic stirrer to obtain a geopolymer-based super-hydrophobic coating.

[0060] Step 6, spraying or brushing on a cement-based surface cured for 28 days:

[0061] Using brushing or spraying, apply the prepared geopolymer-based super-hydrophobic coating to a cement-based surface cured for 28 days, and perform normal temperature curing to obtain a geopolymer-based super-hydrophobic coating for a cement-based surface. The total thickness of the coating is 0.7 mm. Example 3

[0062] A method for preparing a geopolymer super-hydrophobic coating with high adhesion, the specific steps are as follows:

[0063] Step 1, preparation of cement-based material:

[0064] Put portland cement, fine sand, and water into a mill in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0065] Step 2, preparation of alkali activator:

[0066] Mix 14.7 g sodium silicate and 50 g H2O in a magnetic stirrer at 800 rmp / min for 15 minutes, seal and store for 24 hours before use, to obtain an alkali activator with modulus of 2.0.

[0067] Step 3, preparation of geopolymer precursor:

[0068] Take 50g of slag and the prepared alkali activator in step 2, mix and stir for 10 minutes to obtain a flowable geopolymer precursor.

[0069] Step 4, preparation of modified liquid:

[0070] Dissolve 10g of n-octyl triethoxysilane and 1% of nano-TiO2 (30nm) by total mass in 50g of deionized water, magnetically stir at room temperature for 3.5h at a speed of 1000rmp / min.

[0071] Step 5, modification of geopolymer coating:

[0072] Add the modified liquid to the geopolymer precursor, stir at 30°C with a magnetic stirrer at a speed of 850 rmp / min for 45min to obtain a geopolymer-based super-hydrophobic coating.

[0073] Step 6, spray or brush on the cement-based surface maintained for 28d:

[0074] Using brushing or spraying, apply the prepared geopolymer-based super-hydrophobic coating to the cement-based surface maintained for 28d, and perform normal temperature curing to obtain a geopolymer-based super-hydrophobic coating for the cement-based surface. The total thickness of the coating is 0.7mm. Example 4

[0075] A method for preparing a high-adhesion geopolymer super-hydrophobic coating, the specific steps are:

[0076] Step 1, preparation of cement-based material:

[0077] Put portland cement, fine sand and water into a mill in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0078] Step 2, preparation of alkali activator:

[0079] Mix and stir 14.7g of sodium silicate and 50g of H2O in a magnetic stirrer at a speed of 800rmp / min for 15 minutes, seal and store for 24 hours before use to obtain an alkali activator with a modulus of 2.0.

[0080] Step 3, preparation of geopolymer precursor:

[0081] Take 50g of slag and the prepared alkali activator in step 2, mix and stir for 10 minutes to obtain a flowable geopolymer precursor.

[0082] Step 4, preparation of modified liquid:

[0083] 10g n-octyltriethoxysilane and 2% of nano-TiO2 (30nm) by mass were dissolved in 50g of deionized water, and magnetically stirred at room temperature for 3.5h at a speed of 1000rmp / min.

[0084] Step 5, modification of geopolymer coating:

[0085] The modified liquid was added to the geopolymer precursor, and stirred at 30°C using a magnetic stirrer at a speed of 850rmp / min for 45min to obtain a geopolymer-based superhydrophobic coating.

[0086] Step 6, spraying or brushing on a cement-based surface cured for 28d:

[0087] The prepared geopolymer-based superhydrophobic coating was applied to the cement-based surface cured for 28d by brushing or spraying, and cured at room temperature. The resulting geopolymer-based superhydrophobic coating for the cement-based surface had a total thickness of 0.7mm.

[0088] As can be seen from Figure 1 , the geopolymer-based superhydrophobic coating can construct a hydrophobic layer on the surface of the cement-based material, and as can be seen from Figure 2 , the prepared cement-based material coated with the geopolymer-based superhydrophobic coating has a certain roughness on the surface. Example 5

[0089] A method for preparing a geopolymer-based superhydrophobic coating with high adhesion, comprising the following steps:

[0090] Step 1, preparation of cement-based material:

[0091] Put portland cement, fine sand and water into a mill in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0092] Step 2, preparation of alkali activator:

[0093] Mix 14.7g of sodium silicate and 50g of H2O in a magnetic stirrer at a speed of 800rmp / min for 15min, and seal and store for 24h before use to obtain an alkali activator with a modulus of 2.0.

[0094] Step 3, preparation of geopolymer precursor:

[0095] Weigh 50g of slag and the alkali activator prepared in step 2, mix and stir for 10min to obtain a geopolymer precursor in a flowable state.

[0096] Step 4, preparation of modified liquid:

[0097] 10g n-octyltriethoxysilane and 3% of nano-TiO2 (30 nm) by mass were dissolved in 50 g of deionized water, and magnetically stirred at room temperature for 3.5 h at a speed of 1000 rmp / min.

[0098] Step 5, modification of geopolymer coating:

[0099] The modified liquid was added to the geopolymer precursor, and stirred at 30°C for 45 min using a magnetic stirrer at a speed of 850 rmp / min, to obtain a geopolymer-based super-hydrophobic coating.

[0100] Step 6, spraying or brushing on a cement-based surface cured for 28 d:

[0101] The prepared geopolymer-based super-hydrophobic coating was applied to a cement-based surface cured for 28 d by brushing or spraying, and cured at room temperature, to obtain a geopolymer-based super-hydrophobic coating for a cement-based surface. The total thickness of the coating was 0.7 mm. Example 6

[0102] A method for preparing a geopolymer super-hydrophobic coating with high adhesion, comprising the following steps:

[0103] Step 1, preparation of a cement-based material:

[0104] Silicate cement, fine sand and water were placed in a mill in a mass ratio of 1:2.4~3:0.4~0.6 to prepare M30 mortar.

[0105] Step 2, preparation of an alkali activator:

[0106] 14.7 g of sodium silicate and 50 g of H2O were mixed and stirred in a magnetic stirrer at a speed of 800 rmp / min for 15 min, and sealed and stored for 24 h before use, to obtain an alkali activator with a modulus of 2.0.

[0107] Step 3, preparation of a geopolymer precursor:

[0108] 50 g of slag and the alkali activator prepared in step 2 were weighed and mixed and stirred for 10 min, to obtain a geopolymer precursor in a flowable state.

[0109] Step 4, preparation of a modified liquid:

[0110] 5 g of n-octyltriethoxysilane, 5 g of propyltrimethoxysilane and 2% of nano-TiO2 by mass were dissolved in 50 g of deionized water, and magnetically stirred at room temperature for 3.5 h at a speed of 1000 rmp / min.

[0111] Step 5, modification of geopolymer coating:

[0112] The modified liquid is added into the geopolymer precursor, and stirred at 30°C for 45 min at a speed of 850 rpm / min using a magnetic stirrer to obtain a geopolymer-based super-hydrophobic coating.

[0113] Step 6, spray or brush on the cement-based surface maintained for 28d:

[0114] The prepared geopolymer-based super-hydrophobic coating is applied to the cement-based surface maintained for 28d by brushing or spraying, and then normal temperature curing is performed, and the obtained product is a geopolymer-based super-hydrophobic coating for a cement-based surface. The total thickness of the coating is 0.7 mm.

[0115] Experimental Example 1: Static water contact angle test

[0116] To test the water molecule penetration resistance of the geopolymer super-hydrophobic coating prepared in Examples 1-5 in a 3.5% NaCl solution, the test blocks are soaked in a 3.5% NaCl solution for 0h, 24h, 48h, 72h, and 96h, and then static water contact angle tests are performed. The static contact angle values of each example are shown in Table 1.

[0117]

[0118] As can be seen from Example 1 in Table 1, without adding organic materials to the modified liquid, the static contact angle of the prepared coating is greatly reduced, the coating is a hydrophilic coating, and water can easily penetrate into the coating, which will reduce the service life of the coating and is not conducive to the protection of the coating for the cement-based material. As can be seen from Example 2 in Table 1, without adding nano-TiO2 to the modified liquid, the static contact angle of the prepared coating is 132°, which is significantly lower than the static contact angles of Examples 3-6. This indicates that the organic materials and nano-TiO2 in the modified liquid must be added at the same time to ensure a larger static contact angle, increase the hydrophobicity of the coating, prevent salt water from entering the coating, increase the service life of the coating, and better protect the cement-based material from external influences.

[0119] As can be seen from Examples 3-6 in Table 1, with the increase of the amount of nano-TiO2 (30 nm), the hydrophobic angle first increases and then decreases, and reaches 157° when the amount of nano-TiO2 is 2%. Due to the presence of nano-structures, the surface will have a nano-scale roughness, and the air retention in the nano-pores will cause the contact area between the liquid and the solid to decrease, and the solid-liquid and liquid-air surfaces will jointly form a composite surface, which explains why the contact angle of the liquid droplets on the solid surface is extremely large and the rolling angle is extremely small. According to the Cassie-Baxter model:

[0120]

[0121] wherein represents the ratio of the liquid-solid contact area to the total area of the composite interface, represents the actual contact angle of the liquid on the solid surface. The Cassie-Baxter equation shows that the wettability of the solid surface is determined by both the chemical composition of the surface and the roughness factor of the surface.

[0122] With the extension of the immersion time in 3.5% NaCl solution, the static water contact angle of the coating of each example shows a downward trend, and it can be seen that the static water contact angle of the present application is less affected by the corrosion environment, and the downward trend of the value is smaller, and the water contact angle after 96h of immersion can still reach 145°.

[0123] Experimental Example 2: Wear resistance test

[0124] The adhesion performance of the coating was evaluated by sandpaper rubbing experiment. The super-hydrophobic coating surface obtained in Example 2 was repeatedly polished with 320# sandpaper, and the sandpaper was moved back and forth with a distance of 5cm under a 200g weight. Different cycle times (10 times, 20 times, 30 times, 40 times, 50 times) were set, and the static contact angle after each cycle was tested. The sandpaper wear performance curve is shown in Figure 3 Figure 3 The left vertical coordinate on the left represents the contact angle, and the right vertical coordinate represents the sliding angle. The upper broken line represents the change of the contact angle at different rubbing times, and the lower broken line represents the change of the sliding angle at different rubbing times.

[0125] From Figure 3 it can be seen that the static contact angle of the super-hydrophobic coating surface prepared in Example 2 before polishing is 157.2°, and after 50 times of repeated polishing, the static contact angle is 147°. The static contact angle is still above 145°, and the sliding angle is below 10°, which indicates that the super-hydrophobic coating prepared by the present application has good wear resistance and can improve the service life of the coating.

[0126] Experimental Example 3: Adhesion test

[0127] In order to confirm that the geopolymer-based super-hydrophobic coating has excellent adhesion with the cement base, the prepared geopolymer-based super-hydrophobic cement base sample was placed on a material testing machine and stretched to the failure of the test piece at a speed of 5mm / min. The maximum stress of the test piece was recorded. The tensile curve during the test is shown in Figure 4 Figure 4 From it can be found that the maximum adhesion stress of the geopolymer-based super-hydrophobic coating and the cement base material can reach 0.3MPa, which indicates that the incorporation of the geopolymer coating greatly improves the adhesion strength of the super-hydrophobic coating and the cement base.

[0128] Figure 5 is a micro-morphology diagram of the surface of the geopolymer-based super-hydrophobic coating. From Figure 5 ​As can be seen, the geopolymer and nanomaterials, n-octyl triethoxysilane and the like are interwoven to form an interpenetrating network structure, and the prepared coating has a micro-nano structure, which makes the super-hydrophobicity of the coating possible.

[0129] Therefore, the application adopts the above structure to prepare a high-adhesion geopolymer coating for a cement-based surface, and the prepared geopolymer super-hydrophobic cement-based coating meets the requirements of super-hydrophobic materials, uses a new type of inorganic coating, geopolymer, improves the bonding strength of the coating and the base, has excellent adhesion, and has the advantages of simple process, high efficiency, non-toxicity, environmental protection, low carbon and the like.

[0130] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: it can still modify or equivalently replace the technical solutions of the present application, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for the production of a high-bonding geopolymer coating for cement-based surfaces, characterized by: The method comprises the following steps: (1) mixing sodium silicate and H2O to obtain transparent alkali activator with modulus of 1.6-2.0; (2) weighing slag and alkali activator to make the molar ratio of Si / Al 2.8-3.6, and then mixing and stirring to obtain flowable geopolymer precursor, the mass ratio of sodium silicate, water and slag being 14-15:50:50; (3) mixing organic material and nano-TiO2 in water to obtain modified liquid; (4) adding the modified liquid into the geopolymer precursor to obtain super-hydrophobic coating; (5) brushing or spraying the prepared super-hydrophobic coating on the surface of cement-based material after curing for 28 days to obtain cement-based super-hydrophobic surface coating. In step (3), the mass ratio of organic material to water in the modified liquid is 10:50, the addition amount of nano-TiO2 is 1-3% of the total mass of the modified liquid, the organic material is one of n-octyl triethoxysilane or propyl trimethoxysilane or a mixture, and the organic material is mixed with nano-TiO2 and stirred for 3-4 hours to obtain the modified liquid. In step (1), the particle size of nano-TiO2 is 30 nm.

2. A method of producing a high-cohesion geopolymer coating for cement-based surfaces according to claim 1, characterized in that: In step (1), sodium silicate and H2O are mixed for 15 minutes, and sealed and stored for 24 hours before use.

3. A method of preparing a high bond geopolymer coating for cement-based surfaces according to claim 1, characterized in that: In step (2), the solid-liquid ratio is 0.9-1.1, and the geopolymer precursor is obtained after stirring for 20 minutes.

4. A method of preparing a high bond geopolymer coating for cement-based surfaces according to claim 1, characterized in that: In step (5), the mass ratio of Portland cement, fine sand and water in the cement-based material is 1:2.4-3:0.4-0.

6.

5. A method of preparing a high bond geopolymer coating for cement-based surfaces according to claim 1, characterized in that: The total thickness of the coating formed in step (5) is between 0.5 and 4 mm.

6. A method of preparing a high bond geopolymer coating for cement-based surfaces according to claim 1, characterized in that: The total thickness of the coating formed in step (5) is between 2.5 and 3 mm.

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